Knob lock



April 14, 1959 L. MAYON- KNOB LOCK Filed Nov. 5, 1952 INVENTOR LEON MAYON N w W ATTORNEYJ United States Patent KNOB LOCK Leon Mayon, Philadelphia, Pa., assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Application November 5, 1952, Serial No. 318,927

2 Claims. (Cl. 188-73) The present invention relates to locking means and more particularly to a device for maintaining a rotatable knob or index finger of a control element in a preselected setting. Furthermore, the invention may be employed with suitable control devices such, for example, as the type used in electrical and electronic devices, rotatary switches and the like whereby the moulded rotatable control knob or dial thereof may be locked in a preselected setting without danger of accidental rotative movement thereof from its initial setting and without applying suflicient distorting forces to the knob or dial during the locking thereof to cause breaking or cracking of the knob or dial.

An object of the present invention is to provide a new and improved locking device suitable for use with a control element of a rotatable type switch or the like.

Another object of the invention is the provision of a device for locking the rotatable control knob of a control device in a selected setting Without applying any distorting forces thereto.

Another object of the invention is the provision of a locking device for an adjustable dial having means for maintaining the dial in an adjusted position.

A still further object of the invention is the provision of a locking device for a control device which is economical to manufacture, reliable in operating, and which possesses all the qualities of durability in service.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. 1 is a plan view of a control device illustrating the locking device of the present invention attached thereto;

Fig. 2 is an enlarged fragmentary sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is an enlarged top plan view of the locking device of Fig. 1;

Fig. 4 is an inverted plan view of the locking device;

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 3;

Fig. 6 is an enlarged top plan view of an alternative arrangement of the device of Fig. l; and,

Fig. 7 is a sectional view taken on the line 77 of Fig. 6.

Referring now to the drawing wherein like reference characters designated like parts throughout the several views and more particularly to Fig. 1 thereof, the device of the present invention is generally indicated by the reference character 10 and as illustrated is attached to a fiooder 11 similar to the device shown and claimed in the copending application of Lewis E. Kissinger, Serial No. 297,193, and filed July 3, 1952.

The flooder comprises a casing 12 having sealed therein a. rheostat 13, the rheostat being provided with an actuating shaft 14 journalled in a sleeve 15 carried by the rheostat casing. Secured to the shaft 14 in any suitable manact such, for example, as by a screw 16 is a moulded 2,881,867 Patented Apr. 14, 1959 2 actuating knob or index member 17 whereupon the rheostat may be actuated to difierent settings about the graduated scale 18 inscribed on the casing 12.

The knob comprises a substantially conical shaped portion 19 having formed thereon an index pointer 21 adapted to be moved in registration with the graduation on the scale 18 corresponding to the desired setting required to function the device when a predetermined period of time has elapsed, such operation and the purpose intended being clearly set forth in the aforesaid copending application. Since it is essential that the rheostat remain in the preselected setting to produce the desired results the locking device 10 is specifically constructed and arranged to lock the knob 17 in its adjusted position whereupon accidental rotation of the knob is prevented and thus assuring functioning of the device when the time interval has elapsed.

The locking device comprises a substantially U-shaped member 22 composed of any material suitable for the purpose such, for example, as spring steel or the like and comprises a pair of mutually spaced arms 23-24. As clearly shown on Fig. 2 the arm 24 is disposed between the flat surface 25 of the knob 17 and the flat surface 26 of the flooder casing 12.

Arm 24 has formed thereon a downwardly extending lip or lug 27 disposed within a recess 28 arranged in the casing 12. By this arrangement shifting of the locking device is prevented.

As more clearly shown on Figs. 4 and 5 the arm 24 is provided with a centrally disposed opening 29 having a pair of diametrically disposed inclined thread engaging members or lugs 31 bordering thereon and offset with respect to the plane of the arm 24 in such a manner as to threadedly engage the threads 30 formed on the shank of the locking screw 32 as the screw is threaded therethrough and into the recess 33 formed in the casing 12.

The arm 23 is provided with a centrally disposed opening 34 in alignment with the opening 29 through which the shank 30 of the screw 32 freely passes, the head 35 thereof being adapted to move into engagement with the arm 23 as the screw is driven home. When this occurs, as clearly shown on Fig. 2, the arm 23 is moved into locking engagement with the conical portion 19 of the knob 17, whereupon the pair of pointed portions or gripping teeth 36 formed on the arm 23 at the extremities of the semicircular recess 37 are forced into engagement with the conical portion 19 an amount sufficient to lock the knob and prevent accidental rotation thereof.

Since the lug 27 is free to move upwardly in the opening 28 until arm 24 engages the surface 25, portion 19 of the knob is clamped between arms 23 and 24 and hence no bending moment, which would tend to break the knob, is applied to the portion 19. Lug 27 being engaged in opening 28 and the lock 10 secured to the knob, rotation of the knob is prevented.

Referring now to the device of Figs. 6 and 7 it will be noted that the structure thereof is similar to the device illustrated in Figs. 1 to 5 except that in lieu of the gripping teeth 36 a lip 38 is formed on the arm 23 for movement into locking engagement with the inclined portion 19 of the knob 17 thereby to lock the knob in a preselected setting.

From the foregoing, it will be understood that a new and improved locking device has been devised for maintaining a rotatable knob or dial, as the case may be, in a preselected setting without danger of accidental rotative movement thereof from its initial setting and without applying suificient distorting forces thereto during the locking thereof to cause breaking or cracking of the knob or dial.

Obviously many modifications and variations of the present invention are possible in the light of the above "ice s. teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A device for locking a control knob in a preselected setting comprising a fixed open end spring lock folded to form a pair of mutually spaced substantially parallel members, one of the members being provided with an opening, a pair of diametrically disposed elements on the other member and ofiset at an angle'with respect to the plane of said other member, each of said elements terminating in an arcuate portion forming an aperture in alignment with said opening, a pair of mutually compl'ementary knife edge thread engaging'members respectively formed on the elements and ofiset with respect to each other, said thread engaging members bordering on said aperture, and a bolt disposed within said opening and aperture and having a head in abutting engagement with said one member and a threaded shank in close fitting threaded engagement with each of said knife edge thread engaging members for forcing said one member in locking engagement'with said knob as the bolt is tightened.

2. In a control device, in combination, a knob on said device settable at will to difierent settings for regulating the device, a conical portion on said knob, an open end spring lock mounted on the device and folded toform two mutually spaced substantially parallel members, one of the members being provided with an opening, a bolt having a threaded shank freely passing through said opening', a pair of diametrically disposed elements on the other member and oifset at an angle with respect to the plane of said other member, each of said elements terminating in a semicircular portion forming an aperture in alignment with said opening, a pair of mutually complementar-y knife edge thread'engagingmembers respectively formed on the elements and offset with respect to each other, said threaded engagingmembers 'borderingon said aperture for close fitting threaded engagement with substantially one turn of thread on said threaded shank, and a head on said boltmovable into engagement with said one member for maintaining said one member in locking engagement with said conical portion as the bolt is tightened.

References Cit'edin the file of this patent UNITED STATES PATENTS 1,229,693 Wilson- 11.111612, 1917 1,290,382 Slaughter Jan. 7, 1919 1,523,305 Spiro Jan; 13, 1925 1,588,039 Monosrnith June 8, 1926 2,436,921 Goldstine et al. Mar; 2, 1248' 2,486,723 Thompson Nov. 1, I949 

